Boiling dough allows bread to be thinner than paper

To create the impossibly thin crust of the iconic Tsubu Anpan, Japanese bakers rely on a technique called yude-moji, or boiling-kneading. By heating the dough to exactly 60 degrees Celsius during the mixing process, they gelatinize 70 percent of the starch granules. This chemical shift transforms the dough into a flexible, translucent film just 0.2 millimeters thick. It creates a structural paradox: a bread skin that is thinner than a sheet of paper yet strong enough to contain a heavy, dense core of sweet bean paste without leaking or tearing.